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    • High CPU utilization and performance imbalance alerts
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/High_CPU_utilization_and_performance_imbalance_alerts
      Frequent performance imbalance alerts on one node Event: Cluster Load Imbalance Threshold Breached The performance capacity used counter indicates a load difference of 74% between the nodes on cluster...Frequent performance imbalance alerts on one node Event: Cluster Load Imbalance Threshold Breached The performance capacity used counter indicates a load difference of 74% between the nodes on cluster XXX-XXX-XXX and has triggered a WARNING event based on the system threshold of 30% CPU utilization at 70+ % constantly despite Low IOPS Top CPU domain was Host OS , mostly from mgwd from the output of top command PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND
    • What does the wafltop output mean and how can it be interpreted?
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/What_does_the_wafltop_output_mean_and_how_can_it_be_interpreted
      The format of the volume name will be: aggregate:volume:protocol:message in the output The name of the Aggregate the Volume resides in Refers to some internal WAFL operations that may not be classifie...The format of the volume name will be: aggregate:volume:protocol:message in the output The name of the Aggregate the Volume resides in Refers to some internal WAFL operations that may not be classified in other operation types, but are background in nature NVlog utilization is shown in terms of average percentage of the log used per CP. I/O utilization refers to the amount of data read or written in MB/s and IOPS.
    • What does ONTAP do with available IDLE cycles on the storage controller?
      https://kb.netapp.com/on-prem/ontap/OHW/OHW-KBs/What_does_ONTAP_do_with_available_IDLE_cycles_on_the_storage_controller
      ONTAP is opportunistic, when there are available IDLE CPU cycles (IDLE time), instead of wasting the IDLE time, ONTAP can and will use as much of the available time as possible to run background and s...ONTAP is opportunistic, when there are available IDLE CPU cycles (IDLE time), instead of wasting the IDLE time, ONTAP can and will use as much of the available time as possible to run background and scheduled tasks such as: This increased latency is expected since the storage system becomes busy with work it is doing in the background (by design), when the work is complete, utilization and latency can drop back to the normal levels.
    • High CPU utilization when Continuous Segment Cleaning is enabled
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/High_CPU_utilization_when_Continuous_Segment_Cleaning_is_enabled
      Applies to VMware Datastores CIFS FAS 8040 ONTAP 9.7P9 Continuous Segment Cleaning (CSC) SSD aggregates Issue Performance issue (latency) in VMware datastores and in CIFS access High CPU utilization i...Applies to VMware Datastores CIFS FAS 8040 ONTAP 9.7P9 Continuous Segment Cleaning (CSC) SSD aggregates Issue Performance issue (latency) in VMware datastores and in CIFS access High CPU utilization in the node most of the time Node is constantly reading data from SSD aggregates but reads don't correspond with user workload
    • High Latency Observed On SSD Model X356_S16333T8ATE with NA04 Firmware
      https://kb.netapp.com/on-prem/ontap/OHW/OHW-KBs/High_Latency_Observed_On_SSD_Model_X356_S16333T8ATE_with_NA04_Firmware
      Applies to X356_S16333T8ATE Issue 100 ms disk latency with little I/O reported by ActiveIQ. Repeat every 13-13.5 hours. System event log messages for SCSI sense errors on multiple shelves and disks, a...Applies to X356_S16333T8ATE Issue 100 ms disk latency with little I/O reported by ActiveIQ. Repeat every 13-13.5 hours. System event log messages for SCSI sense errors on multiple shelves and disks, around the time the disk latency occurs. Example: [node_name: scsi_cmdblk_strthr_admin: scsi.cmd.checkCondition:error]: Disk device 0a.00.11: Check Condition: CDB 0x28:f5385c00:0018: Sense Data SCSI:aborted command - (0xb - 0x2f 0x10 0x0)(6477).
    • How to map an ocs_vserver workload to which volume it came from
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/How_to_map_an_ocs_vserver_workload_to_which_volume_it_came_from
      Applies to ONTAP 9 Copy offloaded operations appearing as ocs_vserver Description In ONTAP 9 and qos statistics output, if the top workload of a node's resources is ocs_vserver, it can be difficult to...Applies to ONTAP 9 Copy offloaded operations appearing as ocs_vserver Description In ONTAP 9 and qos statistics output, if the top workload of a node's resources is ocs_vserver, it can be difficult to narrow down where it comes from This article gives a method to identify where it is coming from
    • High CVO nvlog latency due to overutilized disks
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/High_CVO_nvlog_latency_due_to_overutilized_disks
      Applies to ONTAP 9 Cloud Volumes ONTAP (CVO) Issue High NVLOG latency is seen Looking at disks, there may be i/o queued but statit will show high latencies
    • Only "-total-" when filtering for volume in "qos statistics volume latency show"
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/Only_total_when_filtering_for_volume_in_qos_statistics_volume_latency_show
      Cluster::> qos statistics volume latency show -volume vol1 -vserver svm1 Workload ID Latency Network Cluster Data Disk --------------- ------ ---------- ---------- ---------- ---------- ---------- -to...Cluster::> qos statistics volume latency show -volume vol1 -vserver svm1 Workload ID Latency Network Cluster Data Disk --------------- ------ ---------- ---------- ---------- ---------- ---------- -total- - 114.08ms 59.00us 149.00us 700.00us 113.17ms -total- - 90.68ms 115.00us 132.00us 1495.00us 88.94ms -total- - 121.99ms 75.00us 129.00us 1398.00us 120.38ms -total- - 141.82ms 53.00us 156.00us 1236.00us 140.38ms -total- - 97.02ms 74.00us 121.00us 2.80ms 94.02ms
    • Slowness redirecting Documents and Desktops to ONTAP after Windows restart
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/Slowness_redirecting_Documents_and_Desktops_to_ONTAP_after_Windows_restart
      Applies to ONTAP 9 Windows desktops VDI such as Citrix, VMware Horizon or other VMs Folder redirection for Desktop and Documents folders stored on a CIFS share in ONTAP, mapped as a drive Issue Slowne...Applies to ONTAP 9 Windows desktops VDI such as Citrix, VMware Horizon or other VMs Folder redirection for Desktop and Documents folders stored on a CIFS share in ONTAP, mapped as a drive Issue Slowness loading a share after Windows is rebooted or logging in Windows loads, but Windows Explorer and the desktop freeze Login times may be a few minutes to 10 or 15 minutes ONTAP has low latency in 1 ms range
    • High Node utilization alert due to heavy CIFS SMB signing
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/High_Node_utilization_alert_due_to_heavy_CIFS_SMB_signing
      Applies to ONTAP 9 Active IQ CIFS Issue Active IQ Unified Manager reports high node utilization or there can be absolutely no issue but customerstill wants us to check for he utilization of node This ...Applies to ONTAP 9 Active IQ CIFS Issue Active IQ Unified Manager reports high node utilization or there can be absolutely no issue but customerstill wants us to check for he utilization of node This may or may not be followed by increased latency.
    • Snapmirror Throughput limited by CPU
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/Snapmirror_Throughput_limited_by_CPU
      Applies to ONTAP Snapmirror Issue Snapmirror is limited independently from count of used ports